For introducing a liquid medicament into a patient's body catheter/needle assemblies have been used. U.S. Pat. No. 5,470,318 discloses such an assembly including a hollow needle for puncturing a region of interest in the body. A flexible tube is inserted through the hollow needle and a liquid medicament is introduced through the tube into the body. Medicaments which are contained in pressure sensitive capsules can not be delivered by means of such an injection device because the capsules would break and would be destroyed because of the pressure exerted on them while they are injected.